The four options at a glance
The four ways to pay for solar
| Cash purchase | Solar loan | Solar lease | Power purchase agreement (PPA) | |
|---|---|---|---|---|
| Who owns the system | You | You | The leasing company | The PPA provider |
| What you pay | Full price up front | Monthly loan payment to a lender | Fixed monthly payment for the equipment | A per-kWh price for the electricity the system produces |
| Who receives Illinois Shines REC payments | Typically the Approved Vendor, which may pass value to you; the Disclosure Form states how | Same as purchase | Typically the system owner (the leasing company); the Disclosure Form states how | Typically the system owner (the PPA provider); the Disclosure Form states how |
| Who receives the ComEd DG Rebate | Typically you as system owner, if you elect it | Typically you as system owner, if you elect it | Typically the system owner | Typically the system owner |
| Maintenance and monitoring | Yours, plus manufacturer warranties | Yours, plus manufacturer warranties | Usually the owner's responsibility | Usually the owner's responsibility |
| Payment escalator | None | Fixed by the loan terms | Common; check the annual percentage | Common; check the annual percentage |
| When you sell the home | System transfers with the house | Loan typically must be paid off or assumed | Lease must be transferred to the buyer or bought out | PPA must be transferred to the buyer or bought out |
| Tax treatment | Yours to discuss with a tax professional | Yours to discuss with a tax professional | The owner's, not yours | The owner's, not yours |
Sources for program mechanics: Illinois Shines Consumer FAQs (REC payments and Disclosure Form); ComEd Net Metering FAQ, 2025. Agreement terms vary by provider; the Disclosure Form and the agreement itself control.
Each option in plain language
Cash purchase
You buy the system outright and own it from day one. There is no monthly payment and no escalator. You are responsible for maintenance beyond manufacturer and workmanship warranties, and you decide whether to take the ComEd Distributed Generation Rebate, which is not reversible once taken. If you sell the house, the system goes with it. The Illinois Shines REC contract is held by the Approved Vendor; how much of the REC value reaches you is spelled out in the Disclosure Form you receive before signing.
Solar loan
You own the system and finance it with a lender. The questions that matter are the interest rate, the term, whether there are dealer fees built into the system price, whether the payment changes at any point, and what happens to the loan when you sell. Because you own the system, the rebate decision and REC pass-through work the same as a cash purchase. Loan approval is the lender's decision, not ours.
Solar lease
A leasing company owns the system on your roof and you pay a fixed monthly amount for the equipment, regardless of how much it produces. The owner typically handles maintenance and monitoring and typically keeps the incentives, including REC payments and any utility rebate. Leases often include an annual escalator. When you sell, the lease has to be transferred to the buyer, who must qualify, or bought out. Read the production guarantee, if any, and the end-of-term options.
Power purchase agreement (PPA)
A provider owns the system and sells you the electricity it produces at a per-kWh price. Your payment rises and falls with production, so it is higher in July than January. Like a lease, the owner typically keeps incentives and handles maintenance, escalators are common, and the agreement must be transferred or bought out at sale. The key questions are the starting price per kWh, the escalator, the production assumptions, and what you pay the utility for electricity the system does not cover.
In every case: you remain the utility's customer and continue to receive a utility bill.
The documents that matter
What to read before you sign anything
The Illinois Shines Disclosure Form. Illinois requires an Approved Vendor or its Designee to give you a standardized Disclosure Form before you sign an installation contract. It states the system size, the cost, how the REC value is handled, how your utility will credit exported electricity, and the terms that affect you. If a company will not show you this form before asking for a signature, stop. Source: illinoisshines.com/faqs.
The agreement itself. Look for: who owns the system, payment amount and escalator, term length, production assumptions and any guarantee, warranty terms and who services the system, transfer and buyout terms, and what happens if the system underperforms.
The ComEd (or municipal utility) billing rules. Your Disclosure Form will reference them, and we explain them in How solar billing works for ComEd customers after net metering changed.
What we do and do not do
ISI's role in financing conversations
We explain the four options and the questions above, using your bills and your situation. We do not give tax, legal, or investment advice, we do not approve loans, and we do not own systems. If you proceed, the licensed installation partner and the Approved Vendor on your project present the actual terms and the Disclosure Form. Our job is that you understand them before you see them.
Frequently asked questions
Solar financing questions
What is the difference between a solar lease and a PPA?
Under a lease you pay a fixed monthly amount for the equipment on your roof. Under a power purchase agreement you pay a per-kWh price for the electricity the system actually produces, so the payment varies with the season. In both cases a third party owns the system.
Who gets the Illinois Shines incentive?
Illinois Shines pays Renewable Energy Credit (REC) payments to the Approved Vendor, which may pass value on to the customer. How that works for your project must be stated in the Disclosure Form you receive before signing. Under a lease or PPA, the system owner typically retains the value. Source: illinoisshines.com.
Is the federal solar tax credit still available?
The IRS states that the Residential Clean Energy Credit (Internal Revenue Code section 25D) is not allowed for expenditures made after December 31, 2025, and that an expenditure is treated as made when installation is completed. Tax treatment of systems owned by a third party is that owner's matter. ISI Energy does not give tax advice; please consult a tax professional. Source: irs.gov, FAQs on Public Law 119-21.
What is a payment escalator?
A clause in a lease or PPA that increases your payment or per-kWh price by a set percentage each year. Ask for the exact percentage and calculate what the payment will be in the final year of the term.
What happens to a solar lease or PPA when I sell my house?
The agreement typically must be transferred to the buyer, who has to qualify with the provider, or bought out. Ask for the transfer and buyout terms in writing before signing.
Does ISI Energy offer financing?
No. ISI Energy is a sales, education, and project-coordination company. Financing is offered by lenders or system owners through the licensed partner on your project. We explain the options so you can evaluate what is presented.
